Visual signal call system



March 3,1936. WHEELOCK 2,032,518

' VISUAL SIGNAL CALL SYSTEM Original Filed Dec. 5, 1929 2 Sheets-Sheet l GOO 000 .3

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VISUAL SIGNAL CALL SYSTEM Original Filed Dec. 5, 1929 2 Sheets-Sheet 2 27227572 57? Jo/m 1'1 W68 el f Patented Mar. 3, 1936 UNITED STATES PATENT OFFICE VISUAL SIGNAL CALL SYSTEM sachusetts Application December 5, 1929, Serial No. 411,164 Renewed August 15, 1934 8 Claims.

1 According to the present invention there are distributed throughout the system a desired number of visual call boards, each one of which is adapted to intermittently display a signal or signals selected by an operator, usually located at a telephone switch board, who can also cause several designated signals to be displayed in sequence. Thus when the system is installed in a hospital, for example, it is possible to successively display the numbers of several physicians 20 who may be located in different parts of the building. The above and other advantageous features of the present invention will hereinafter more fully appear, reference being had to the accompanying drawings, in which,

25 Fig. l is a diagrammatic view illustrating the arrangement of the apparatus entering into the present invention.

Fig. 2 is a horizontal sectional view of one of the signal code setting units.

30 Fig. 3 is a fragmentary view illustrating the operation of the selector mechanism.

Fig. 4 is a diagrammatic view of the whole system illustrating the display of a designated signal call at the stations.

Like reference characters refer to like parts in the different figures.

Referring first to Figs. 1 and 4, the system generally consists of a code setter generally designated by the reference character A preferably located near a telephone switch board where it is convenient to the operator. The code setter A consists of a number of similar units HI, ID, I", each providing a series of operating keys designated l to 9 inclusive, the operation of which will be hereinafter described. The several units III are connected by a multiple conductor cable II to a number of relay devices l2 which are adapted to control the energization of signal display boards B distributed at points where they may be readily observed, each board B providing a number of lamps I3 bearing numbers corresponding in sequence to-the numbers of keys i to 9 inclusive in each unit III of the code setter A. Each series of lamps I 3 is so controlled by its relay I! that when illuminated, a number will be displayed at all the boards 13 corresponding to the number of a depressed key.

The system is adapted to be operated from a suitable source of electrical energy indicated at H to the side of which the code setting units 5 l0 and the signal relays I! are connected through a common conductor ii. The side of the source I is adapted to supply energy to a current interrupting device I8 which is adapted to automatically make and break a circuit leading to a selector ll having a rotatably mounted contact arm I8 adapted to successively engage groups of contacts l9, I9, 19" corresponding in number to the number of units l0, I0, I0" etc., of the code setter A. A suitable operator's switch 10 is provided in the circuit between the side of the source l4 and the signal sender I 8 which when closed is adapted to connect the interrupter l6 and the selector H to the source M, the entire system being deenergized when the switch is 20 open.

Referring now to Figs. 2 and 4, one of the code setting units I0 is shown in detail, and since all of the units are identical in construction, only one need be described. The keys I to 9 inclusive of a unit l0 each provide a shank 2| slidably mounted in the front 22 of the box which encloses the unit, each shank 2| being surrounded by a spring 23 which tends to hold the key in a forward or inoperative position. Each key carries a pair of resilient contact fingers 24 and 25 connected together but insulated from the key, each finger 24 being always in engagement with a bus bar la, 2a or 8a, etc., as the case may be, corresponding to the number of the key on which the finger 24 is mounted. Thus there are nine bus bars numbered la to 9a inclusive all connected to the keys I to 9 inclusive and in sliding engagement therewith. As shown in Fig. 4, the bus bars la to Sc inclusive extend between the several units l0, l0 and I0", so that the several keys designated l of the several units in are always connected to the bus bars la. Furthermore, the bus bars Ia to 9a inclusive are connected to the corresponding number of conductors in the cable II and the conductor connected to the bus bar la is connected to one terminal of the winding 26 of a relay l2,,one contact 21a of which is connected in parallel to all those lamps l3 of the signal boards l2 which when illuminated will show the numeral 1. The bus bar-s 2a, 3a, la etc. are similarly connected to conductors in the cable ll leading to windings 2B of relays l2, the contacts 21a of which lead to the lamps I3 which when illuminated are adapted as to display the numerals 2-3-4, etc. The other terminals oi all of the windings 28 are connected to the common conductor i3 leading to the side of the source 4, as clearly shown in Fig. 4 as are also the contacts 21b 01' all the relays l2. The several series of lamps i3 are all connected in parallel on one side to the side of source i4, so that when any relay i2 is closed by energization of its winding 28, the corresponding series of lamps will be illuminated by closing 01' the relay contacts 21a and 2%.

Referring again to Fig. 2, the finger 25 of each key extends rearwardly and when a key is depressed against the force of the spring 23, the finger 2B is moved out of alinement with the other fingers 23 into close proximity and parallel to a contact bar 28 extending along the rear of the unit, although out of contact therewith. When the key is depressedas shown, it is locked in this'position by a spring pressed latch 23c carried by a shiftable plate 23 through which the shank 2i passes, the latch plate 23 also carrying a series of latches 23a adapted to lock other keys such as 3 and 6 which are also shown as being depressed to bring their fingers 25 into parallel relation with the contact bar 28. The contact bar 23 is mounted on a pivot 23a at one end while its other end is opposed to a magnetic core 30a surrounded by a solenoid 36.

-The bar 23 is normally held out of engagement with the core 38a by means of a spring 3! which also serves to hold the bar 23 away from the fingers 25 of the several depressed keys i, 3, and 4, as shown. One terminal of the solenoid 30 is connected to the common conductor i5 leading to the side of the source i4 while the other terminal thereof is connected to the group of selector contacts designated i9 to which current from the side of the source i4 is adapted to be supplied when the movable arm i8 engages any contact 83. Consequently, when the contact arm i3 engages a contact i9 energization of the solenoid 33 will cause the free end of the bar 28 to be attracted by the core 3011, thereby shifting the bar 28 about its pivot 28a, against the pull of the spring 3i, to simultaneously engage all of the fingers 25 that are in the path of the bar by reason of the depression 0! the corresponding keys. This movement of the bar 28 will also cause its free end to engage a contact 30b connected to the selector contact i9, thereby energizing all of the fingers 25 engaged by the.

bar 23. 7

When the fingers 25 on the keys i, 3, and 4 are so engaged by the energized bar 23, the bus bars la, 3a, and so are simultaneously energized to close the corresponding relays I 2 and lamps 3 bearing the numbers 1, 3, and 4 will be simultaneously illuminated in all oi the signal boards i2 to display the signal 1-3 4 throughout the system. Obviously, the designated lamps will remain illuminated so long as the selector arm i8 remains in engagement with any selector contact l3 and the functioning of the signal sending de vice i3 whereby the selector arm It! will inter-. mittently engage the contacts i9 will next be described.

As shown in Fig. 3, the selector arm i8 is carried by a shaft 32 carrying a ratchet wheel 33. The angular displacement between the teeth 34 01' the ratchet wheel 33 is such that turning the shaft 32 through the displacement or one tooth 34 moves the arm l3 from one contact N to the next contact IQ of any group. An arm 33 carryin a pawl 33 is pivoted on the shaft 32 and the arm 33 is connected by a link 31 to the pivoted armature 38 of a solenoid 33 which when energized is adapted to cause turning of the wheel 34 by the pawl 38 through the displacement of one tooth 34. The armature 33 is also adapted to connect the selector l8 to the side of the source i4 by bridging stationary contacts 40, shown in Fig. 4, energization of the solenoid 33 being under the control of the current interrupting device I8 as will now be described.

One terminal of solenoid 39 is connected to the side of source i4 while its other terminal is connected to a stationary contact ii of the sender i8. The sender I6 provides a filament 42 passing several times around pulleys, freely rotatable, and has one end connected to an anchor post 43 that is in turn electrically connected to the side of the source i6 when the switch 23 is closed. When the filament 32 is at ordinary room temperature, it exerts a pull on a pivoted switch arm 44 so as to hold the free end oi a spring contact 45 carried by the arm M in engagement with the stationary contact ii leading to the solenoid 33. Let it now be assumed that the switch 20 is closed by the telephone operator who has previously depressed keys 3, and 4 so as to display the call signal l-34 upon operation of the mechanism. Upon closing the switch 20, current flows from the side of the source i4 through the filament 42, to the arm 44 through contacts 45 and 4| and -from thence through the solenoid 33. Energization of solenoid 39 will cause the armature 38 to first move the selector arm l8 into engagement with contact i3, as shown in dotted lines, and then bridge contacts 40 to energize solenoid 30. This will shift the bar 28 into engagement with the fingers 25 on the depressed keys i, 3, and 4, thereby illuminating the lamps i3 at all the boards i2 to show the signal 134. As current continues to fiow through the filament 42, with the signal lamps energized,

it will expand and pemiit a spring 84a acting on arm 44 to turn the arm 44 clockwise and cause separation oi the contacts 4i and 45 after the signal lamps i3 have been illuminated a predetermined length of time. a

In order to separate contact 53 from stationary contact 4| with a quick movement, there is preferably employed a throw over device of the type shown in a copending application, Serial No. 291,441, filed July 9, 1928 by Charles L. Hanel, Patent No. 1,868,500 dated July 26, 1932, and assigned to the Signal Engineering 8: Manufacturing Company. As fully shown and described in the aforesaid copending application, the movable contact 45 is composed of resilient material having its central portion cut away to provide spmed fingers 45a with a tongue 46 therebetween, the

fingers 45a and the tongue 46 being Joined together only adjacent to the contact 4| opposite to the points 01 attachment of the fingers 45a to the arm 44 by the screws 41. The tongue 46 is bent into a double loop, shown at 48, near its juncture with contact 43, the free end of the tongue 46 extending in the direction of the arm 44 where it is received in a notch 43 provided in the end of the arm 44. With the parts in the position shown in Fig. 3, the end 01' the tongue 46 is disposed considerably below the resilient fingers 45a, so that the tongue 48 exerts an upward thrust tending to maintain the contact 45 in engagement with the stationary contact 4| that is connected to the solenoid 33 and the contacts 45 and 4| are thus maintained in engage- .ment so long as a pull is exerted on the arm 44 ond unit I.

by the cold filament 42.

When the switch is closed, current flowing through the filament 4| causes it to expand as it heats up, thus permitting the spring 44a to turn the arm 44 in a clockwise direction about its axis. As the arm 44 is thus moved upwardly with respect'to the contact 4|, the end of the tongue 48 in the notch 49 crosses a line joining the free end of the fingers 45a with their points of attachment to the rigid arm 44, whereupon the tongue 46 exerts a thrust tending to separate contact 45 from the contact 4| with a quick movement thereby deenergizing solenoid 89 and breaking the control circuit for the lamps then illuminated as the falling armature 38 separates contacts 40. In other words, the armature 38 breaks all of the lamp relay circuits and limits arcing to the contacts which can be sufiiciently heavy for the currents handled. Since current is no longer flowing through the filament 42, the latter cools and as it contracts, it turns the arm 44 in a counterclockwise direction and swings the notch 49 downwardly until the thrust oi! the tongue 48 snaps the contact back into engagement with the stationary contact 4 I. When this occurs, the circuit through the solenoid 39 is reestablished,

the armature 38 turns the selector arm I! to engage contact 'l9, and the solenoid 30 is energized, thereby drawing'down the contact bar 28' so as to engage whatever fingers 25 are presented to the bar by the depression of keys of the see- In Fig. 4, the keys numbered 2, 4, and 5 are depressed and since the selector arm I8 is engaged with the second selector contact I9, the lamps at the signal boards B will be illumi-' mated to show the signal 2-4-5. The particular construction of the stepping mechanism represented by the armature 38 and its linkage to the ratchet wheel 34 is more fully shown and described in my copending application Serial No. 417,469, filed Dec. 30, 1929, jointly with Charles L. Hanel.

After the signal 24-5 has been displayed a predetermined period, the filament 42 will again expand, thereby permitting the switch contact 45 to again leave contact 4| to extinguish the lamps by again deenergizing solenoid 39. After predetermined intervals, the arm |8 will be moved from the contact I9 to the contact i9" and then from l9 to contact i8 and finally into reengagement with the second contact I! oi this group, whereupon the first signal 1-3-4" will again be shown.

Obviously the signals will continue to be displayed at the signal boards B so long as the keys of the several signal setting units remain depressed. However, as soon as any one answers in response to the showing of a given signal, the switch board operator can cause this signal to be omitted from the cycle by pushing the latch plate 28 of any particular unit from right to left, as viewed in Fig. 2, to release the depressed keys from the latches 29a. The release of the keys oi! a given setting unit will have no effect on the keys of the other units so that the other signals will continue to be shown as long as as any keys remain depressed. After all the persons whose signals have been shown have answered the calls, all of the keys are released and the operator opens the switch 20 whereupon the arm l8 comes to rest in engagement with one of the contacts i9 to |9". Consequently, the operator can observe the position of the arm i8 and so determine which unit I 0 will be first shown when the system is again placed in operation by closing the switch ill. Obviously the cycle oi operations described above will continue indefinitely so long as the switch 20 remains closed and the keys of any one of the signal setting units ID are depressed.

From the foregoing, it is apparent that by the present invention there is provided an automatically operated signal system that is adapted to display visually, certain selected signals, any given signal being shown a predetermined interval after which it is automatically extinguished and another different signal displayed if desired. Due to the cycle of operation employed, it is possible to display several different signal numbers independently of the others so that several persons can be called at one time. This flexibility in operation is believed to render the present system much more effective than signal systems or the type heretofore employed in which it has been possible to sound only one signal at a time. By the present system a given signal will continue to be shown until it is answered, although during this period several other different signals may be displayed and answered. By employing the switch arm 44 to make and break the signal energizing circuits, as well as the selector operating circuit, all arcing is restricted to the switch contacts 45 and 40.

In addition to the above described use of the system in a hospital to noiselessly call the attention of doctors, or other persons, it is equally well adapted for other uses. For example, it can readily be employed ior police purposes to display at certain designated points, on main trafilc arteries, the numbers of stolen automobiles or the numbers of vehicles involved in crimes. The system can also be employed for calling cab numbers at theatres or other public places. In other words, the invention can be used advantageously in any electrical systemin which it is desired to establish the fiow of current in different multiples of branch circuits, in a given sequence.

I claim,

1. In a signal system, a code determining device comprising a plurality of sets of key operated contact members, each of which is individually movable Irom a retracted position to an advanced code determining position, a plurality of common movable contact members, one ior each set of keys, for simultaneously engaging the advanced contact members oi! each set, parallel electrical connections extending between corresponding contact members or the diflerent sets, and means for sequentially causing the movement, one at a time, of the common contact members to engaging position with the advanced contact members or the corresponding set.

2. In a signal system, a code determining device comprising a plurality of sets 01 key operated contact members, each of which is individually movable from a retracted position to an advanced code determining position, a plurality of common movable contact members, one for each set of keys, for simultaneously engaging the advanced contact members of each set, parallel electrical connections extending between corresponding contact members 01' the different sets, a series of electro-magnets Ior individually controlling the common contact members of the several sets, and means for sequentially energizing said electromagnets to cause successive energizations of said electrical connections in accordance with the arrangement of the depressed contact members of each set.

3. In a signal system, a code determining de= vice comprising a plurality of sets or key operated contact members, each or which is individual y movable from a retracted position to an advanced code determining position, a plurality of common movable contact members, one for each set of keys, for simultaneously engaging the advanced contact members of each set, parallel electrical connections extending between corresponding contact members of the diiiferent sets, a series of electro-magnets for individually controlling the common contact members of the several sets, a series of spaced stationary contacts connected separately to said electro-magnets, and means for sequentially energizing said stationary contacts to cause sequential operation of the common contact members by said electro-magnets.

4. In a signal system, a code determining device comprising sets of spaced contacts, individually operable from a non-code to a code determining position, movable bridging members, one for each set of contacts, for simultaneously engaging the operated contacts of each set, electrical connections extending between corresponding contacts of the difierent sets, and means for sequentially causing the movement, one at a time, of said bridging members to close all of the gaps between the contacts 01' each set that are in code determining position.

5. In a signal system, a source of electrical energy, a code determining device comprising sets of contacts, individually operable from a noncode to a code determining position, movable bridging members, one for each set of contacts, for simultaneously engaging the contacts oi. each set that have been moved to code determining position, electrical connections extending between corresponding contacts of the diflerent sets, and means operated from said source for sequentially moving said bridging members to engage the operated contacts of each set to cause successive energizations of said electrical connections from said source in accordance with the diflerent code determinations of the operated contacts.

6. A signal system, a source of electrical energy, a code determining device comprising sets of contacts individually operable from a non-code to a code determining position, electrical connections extending between corresponding contacts of the different sets and energized from one side oi said source, movable bridging members, one for each set of contacts, for simultaneously engaging the operated contacts of a set, and means tor sequentially moving said bridging members, when energized from the other side of said source, to cause the how of current successively through said connections in accordance with the diflerent code determinations of the operated contacts in the different sets.

7. A signal system, a source 01' electrical energy, a code determining device comprising sets of contacts individually operable from a non-code toa code determining position, electrical connections extending between corresponding contacts of the diilerent sets and from one side 01 said source, movable bridging members, one for each set of contacts, for simultaneously engaging the operated contacts of a set, means for sequentially moving said bridging members, when energized trom the other side of said source, to cause the flow of current through said connections in ac-, cordance with the different code determinations of the operated contacts in the different sets, and means operating between successive movements of said members for simultaneously breaking the circuits through all of said connections, indev cause the flow of current through said connections in accordance with the different code determinations of the operated contacts'in the difierent sets, and a pair of contacts connected to all of said bridging members -for simultaneously breaking the circuits through all 01' said connections in the intervals between successive movements of said bridging members. JOHN H. WHEELOCK. 

